High side cutout unit for switches



March 11, 1947. a E SHAW 2,417,219

HIGH SIDE CUT-OUT UNIT FOR SWITCHES Filed June 29, 1943 Patented Max'.11, 1947 HIGH SIDE CUTOUT UNIT FOR SWITCHES Burton E. Shaw, Bristol,Ind., assigner to Penn Electric Switch C0.,

tion of Iowa Goshen, Ind., a corpora- Application June 29, 1943, SerialNo. 492,679

claims. 1

My present invention relates to an actuating unit such as one operatedby high `pressure in a refrigerant line and effecting opening of aswitch which is normally and otherwise controlled by changes intemperature or refrigerant pressure.

One object of the invention is to provide an actuating device of thisgeneral character which may be used in a variety of installations andwhich primarily comprises a unit having self contained pressureresponsive means, an actuating lever operated thereby, a toggle springfor imparting snap action to the actuating lever, and an adjustablerange spring for the actuating lever, which is adjustable while the unitis detached from a control switch or the like on which it is to be laterinstalled.

Another object is to provide an actuating unit which may be installed ona control device when required, thus eliminating the necessity of thedealer stocking both control devices with the actuating unit and otherswithout them.

A further object is to provide an actuating unit in which all themechanism is mounted in a casing of substantially the size and shape ofthe usual bellows housing of a refrigerant motor control switch, suchcasing being readily attached as by iour screws to the housing of acontrol switch in position for an actuating lever thereof to projectinto the housing and operate the main switch therein to ofi positionupon an undesirable condition occurring, such as excessive pressure onthe high side of the refrigerant compressor.

Still a further object is to provide an actuating unit having rangeadjusting means which can be adjusted while the unit is detached from aswitch housing and thereby preset at the factory, so that it is merelynecessary to attach it to the control device when a control device withthe unit is desired for sale by the dealer, the unit having a rangeindicating scale and means to adjust a toggle spring and the rangespring from the exterior of the unit casing.

With these and other objects in view, the invention resides in certainimprovements and in a combination of parts of the device, all as willhereinafter more fully be described and the novel features will bepointed out in the claims appended to the application.

In the accompanying drawings:

Figure 1 is a front elevation of a switch such as shown in theapplication of Harold L. Hawthorn, Serial No. 492,678, filed June 29,1943, with my high pressure cut-out unit mounted thereon;

(o1. o-s3) Figure 2 is an enlarged plan view of the cutout unit,omitting an actuating arm thereof;

Figure 3 is a vertical sectional view through the unit and lookingupward in relation to Fig- 5 ure 2, and

Figure 4 is another vertical sectional View of the unit and lookingtoward the left in Figure 3.

On the accompanying drawing, I have used the reference numeral I0 toindicate generally a switch housing, from which the cover has beenomitted. The housing Ill, as shown, has a back plate and bottom and topplates I2 and I4. A bracket I6 is mounted in the housing lil and carriesa pivot pin i8. Pivoted on the pin E8 is an actuating lever 2Q having anextension 22. For automatically moving the lever 20 and its extension 22in response to a condition such as refrigerant pressure, I provide abellows 24 opposed by a range spring 2B. The bellows 24 is contained ina housing 28 with which a pressure connection can be made at a tting 3D.Secured to the head of the bellows is an operating stem 32 engaging thelower side of a pin 34 carried by the lever 20. Engaging the upper sideof the pin is an end washer 36 for the lower end of the Spring 26. Anend washer 38 is provided for the upper end of the spring and it isnonrotatable relative to an adjusting screw 40, in the usual manner.

The lever 20 and its extension 22 are adapted to actuate a switch arm 42through toggle spring and link mechanism, fully described in said Haw-'thorn application. This connection briefly includes a toggle lever 44pivoted at V points 46 and connected by a toggle spring 48 to the leverextension 22, the lever 44 being connected by a toggle link 50 to thelower end of the switch arm 42, the upper end of the switch arm beingpivoted at 52. The switch arm 42 carries a movable bridging contact 54adapted to bridge a pair of stationary contacts 56. The bridging contactis mounted on a bar 58 extending loosely through the switch arm 42 andis urged in one direction relative thereto by a spring 60. The motion islimited by a pin 62. When the switch is in closed position, it may beopened while the linkage 44-48-50 remains in closed circuit position byengaging an extension 64 of the bridging contact and pushing it towardthe left, as will hereinafter appear.

My actuating unit comprises a casing 66 adapted to be secured to thelower wall I2 of the housing I 0 by four screws 68. These screws pass 55upwardly through openings 'I0 formed in a ange annale "12 around thebase of the housing lit and are threaded into the wall |2.

Within the casing 66 is a frame I4 secured to a wall of the casing 66 asby two screws 76. The frame 14 has a pair of ears 'I8 for supporting apivot pin 80. The frame further has a bottom plate 82 provided with anembossed central part having therein a perforation 8d, as shown inFigure 4. A bellows housing 8B has a tting 83 extending through theopening 84 and the bellows housing is thereby mounted in positionrelative to the frame ld, a lock nut 90 being screwed on the fitting forthis purpose.

Within the housing 86, I provide a bellows 92 which is relatively smallbecause it need respond only to very high pressures. The bellows has anactuating stem 94 extended out of the upper end of the housing 86.

An actuating lever in the form-of a plate 96 is pivoted to the pin 80,the plate having perforated ears 98 for this purpose. The plate 95further has a plurality of flanges |00, |02, |04 and |06. The ange |06is adapted to contact the upper end oi the bellows stem 9d, and toeffect such contact a range spring |08 is provided. The upper end of therange spring is connected to the plate 9E and the lower end is mountedon a plug H0. An adjusting screw ||2 is threaded in the plug and passesthrough an opening ||l in the plate 82, the screw having' outside of theopening a slotted need llt. "he casing 66 has an opening IIS to receivethe head and permit free rotation thereof. v

The plug |||l has an extension terminating in a pointer |22. The pointer|22 travels in a slot |20 of the casing l0 back of a transparent window|20. Suitable indicia are provided for cooperation with the pointer |22to indicate the pressure at which the lever 96 will be moved to cut-outposition, as shown in Figure 1.

For operating the lever 96 with snap action and to have a widediiferential lfor its operation, so that alter high side cut-out occurs,cutin will not be permitted again until there is a substantial reductionin pressure in the bellows housing 86, I provide a toggle or over-centerspring |20. Its ends are capped as at. and |32, the cap |30 engaging aknife edge lower end of the flange |02, and the cap |32 engaging anadjustable pivot |34. The pivot I3@ is threaded in the frame bottomplate 82 and there is an opening |36 in the casing 6B, permitting freerotation of the screw when adjusting it.

In Figure 3, I have shown a lever diagram for the over-center positionsof the toggle spring |28. These are shown by dot and dash lines and theon position of the parts is shown in this figure. The off positioncorresponds to a center indicated by a black dot |38, where the pivotbetween the lower end of the flange |02 and the cap |30 occurs, afterthe high pressure cutout has operated to switch-onf position. The flange|02 is conned in a slot of the frame 'i4 having one side indicated at|40 and its other side indicated at |42. kThe sides |20 and |42 serve asstop surfaces for the flange |02 in the switch-on and switch-offpositions of the actuating means.

The flange |04, when the actuating unit is mounted on the switch housingI0, extends upwardly through a slot |44 in the bottom wall I2, and anactuating arm |46, preferably of insulating material, is secured to theflange |06 by screws |48. The actuating lever is shown in the switch-onposition in Figures 1 and 3, and it will be obvious that when it isrotated counterclockwise the arm |46 will swing toward the left at itsupper end to engage the extension 64 of the bridging contact 54, therebyseparating one of the movable contacts from one of the stationarycontacts to break the circuit until such time as the pressure in thebellows housing 86 recedes to a value permitting the spring |08 toovercome the spring |38 and return the actuating unit to its normalposition.

The arrangement of parts of my device is such that the entire unit is asub-assembly that can be attached or not relative to a switch unit,depending on whether a high side pressure cutout is or is not desired.The device can be entirely fabricated and preadjust'ed at the factory,as it is unnecessary to have any cooperation between the unit and partsof the switch or control device to eifect the adjusting operation. Atthe same time, the device is capable of being readjusted in the field`as to range, the screw head IIB being accessible and upon rotationshowing, by the pointer |22 just what the adjustment is by observancethrough the window |26. The diierential of operation can also beincreased or decreased by moving the screw |34 up or down, respectively.

Some changes may be made in the construe tion and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims any modifiedforms of structure or use of mechanical equivalents which may bereasonably included within their scope without sacrificing any of theadvantages thereof,

I claim as my invention:

1. An actuating unit comprising a casing for attachment to a controlhousing, a frame in said casing, pressure responsive means within saidcasing `and having a threaded tting projecting through said frame andfrom said casing to the exterior thereof for attachment to a pressureline, a. lock nut on said fitting for mounting said pressure responsivemeans relative to said frame, an actuating lever pivoted to said frame,a range spring connected to said actuating lever and having an adjustingscrew carried by said frame and projecting through said casing foroperation from the exterior thereof, said range spring normallyeffecting engagement of said actuating lever with said pressureresponsive means, and a toggle spring interposed between said actuatinglever and said frame to eiect snap action of said actuating lever, saidactuating lever, said range spring, said adjusting screw and said togglespring being all mounted within said casing.

2. An actuating unit comprising a casing for attachment to a controlhousing, a frame in said casing, pressure responsive means mounted onsaid frame, an actuating lever pivoted to saidu frame, toggle means toeffect snap action of said other.

An actuating unit comprising a casing for attachment to a controlhousing, a frame in said casing secured to one wall thereof, pressureresponsive means mounted on said frame and having a tting projectingfrom said casing, thru said frame and to the exterior of said casing forattachment to a pressure line, a retainer coacting with said tting andsaid frame to retain the fitting and said pressure responsive meansassembled relative to said frame, an actuating lever pivoted to saidframe, a range spring connected to said actuating lever, said rangespring normally eiecting engagement of said actuating lever with saidpressure responsive means, and toggle means to elect snap action of saidactuating lever said pressure responsive means, said actuating lever,said range spring and said toggle means being located within saidcasing.

4. An actuating unit of the character described for a control devicehaving a housing, said unit comprising a cup-like casing for directattachment to the housing, pressure operated means comprising a bellowsand a chamber therefor, an actuating element controlled by said pressureoperated means and extending from said casing and into said housing forengaging said device upon operation of said pressure operated means,said actuating element including a bell crank having one arm engageablewith said bellows, a spring connected with said arm to effect suchengagement, said spring and the other arm of said bell crank extendingsubstantially parallel to said chamber, and toggle spring mechanismaligned with said other arm of said bell crank for imparting snap actionto said actu- Number ating element, said bellows, its chamber, saidspring and said toggle spring mechanism being all located within saidcup-like casing.

5. In an actuating unit, a casing for attachment to a housing of acontrol device, frame in said casing, pressure responsive means in saidcasing and carried by said frame, an actuating element pivoted to saidframe within said casing and projecting from the casing and into saidhousing for moving a controlling device therein to apredeterminedposition upon operation of said pressure responsive means, adjustingmeans within said casing and carried by said frame for adjusting therange of operation of said pressure responsive means, said adjustmentmeans having a, manually actuatable part projecting to the exterior ofsaid casing, and a tting for connection with .said pressure responsivemeans, said fitting being carried by said frame whereby the frame, thepressure responsive means, the actuating element and the adjusting meansform a unitary structure independent of said casing.

BURTON E. SHAW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date 2.080,169 2,292,214

Dillman May 11, 1937 Dillman Aug. 4, 1942 Schaefer Dec. 27, 1938

